HIV-1-associated dementia during HAART therapy

Human immunodeficiency virus (HIV-1) is the responsible agent of acquired immunodeficiency syndrome (AIDS), a multi system disorder including the central nervous system (CNS). The CNS is an immunological privileged site providing a sanctuary and reservoir for HIV-1. Monocytes derived macrophages (MDM) and microglia play a critical role in the development of HIV-associated dementia (HAD). Although the use of highly active antiretroviral therapy (HAART) has led to a strong reduction of HAD incidence, the prevalence of minor HIV-1 associated cognitive impairment appears rising among AIDS patients. Various factors including toxicity, insurgence of drug resistance and sometimes limited access to HAART, contribute to this phenomenon. Independent evolution of drug resistance mutations in several areas of the CNS may emerge as consequence of incomplete suppression of HIV-1, probably related to poor penetration of antiretroviral drugs into CNS. The emergence of resistant virus in the CNS may considerable influence the outcome of neurological disease and also the reseeding of HIV-1 in the systemic circulation upon failure of therapy. In this review, we outline the current state of knowledge regarding the pathophysiology of CNS injury in HIV-1 infection and will focus on the effects of HAART on CNS.